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| Title | Structural basis of chiral wrap and T-segment capture by DNA gyrase. |
|---|---|
| Journal, issue, pages | Proc Natl Acad Sci U S A, Vol. 121, Issue 49, Page e2407398121, Year 2024 |
| Publish date | Dec 3, 2024 |
 Authors | Elizabeth Michalczyk / Zuzanna Pakosz-Stępień / Jonathon D Liston / Olivia Gittins / Marta Pabis / Jonathan G Heddle / Dmitry Ghilarov /   |
| PubMed Abstract | Type II topoisomerase DNA gyrase transduces the energy of ATP hydrolysis into the negative supercoiling of DNA. The postulated catalytic mechanism involves stabilization of a chiral DNA loop followed ...Type II topoisomerase DNA gyrase transduces the energy of ATP hydrolysis into the negative supercoiling of DNA. The postulated catalytic mechanism involves stabilization of a chiral DNA loop followed by the passage of the T-segment through the temporarily cleaved G-segment resulting in sign inversion. The molecular basis for this is poorly understood as the chiral loop has never been directly observed. We have obtained high-resolution cryoEM structures of gyrase with chirally wrapped 217 bp DNA with and without the fluoroquinolone moxifloxacin (MFX). Each structure constrains a positively supercoiled figure-of-eight DNA loop stabilized by a GyrA β-pinwheel domain which has the structure of a flat disc. By comparing the catalytic site of the native drug-free and MFX-bound gyrase structures both of which contain a single metal ion, we demonstrate that the enzyme is observed in a native precatalytic state. Our data imply that T-segment trapping is not dependent on the dimerization of the ATPase domains which appears to only be possible after strand passage has taken place. |
 External links | Proc Natl Acad Sci U S A / PubMed:39589884 / PubMed Central |
| Methods | EM (single particle) |
| Resolution | 2.6 Å |
| Structure data | EMDB-51339, PDB-9ggq: |
| Chemicals |  ChemComp-MG:  ChemComp-MFX:  ChemComp-HOH: |
| Source |
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 Keywords | ISOMERASE / DNA gyrase / type II topoisomerase / moxifloxacin / DNA crossover |
escherichia coli (E. coli)
escherichia phage mu (virus)